Even though the Market Vectors Semiconductor ETF (NYSE:SMH) is off 5% for the year, it’s in the midst of a scorching rally the past couple weeks, with a return of 12%. This compares to a gain of 4% for the S&P 500

Is it time to consider the semis? Maybe so.

SMH is based on a market-cap weighted index of 25 U.S.-listed companies. The top holdings include Intel (NASDAQ:INTC), Taiwan Semiconductor Manufacturing (NYSE:TSM), Texas Instruments (NYSE:TXN), ARM Holdings (NASDAQ:ARMH) and ASML (NASDAQ:ASML). They account for about 52% of the total assets in the ETF.

The fee structure is also reasonable, with an expense ratio of 0.35%.

As should be no surprise, SMH’s holdings are volatile. For the year, Intel’s shares are off by 16%, while ARM’s are up 34%.

Of course, the semiconductor industry is highly sensitive to the global economy, which has been slowing down lately. Another problem is periodic supply-chain disruptions. Recent examples include Japan’s massive earthquake and the flooding in Thailand.

What’s more, the industry is undergoing some major secular changes. PC sales growth has been suffering a long-term decline, which has been a big drag for Intel. Then again, mobile devices have continued to grow at a rapid clip, a trend that has propped up ARM’s shares.

SMH does have a good amount of exposure to mobile. In addition to ARM, other holdings include Skyworks Solutions (NASDAQ:SWKS), Broadcom (NASDAQ:BRCM), Taiwan Semiconductor and ASML. All have posted double-digit returns for 2012. However, it’s disappointing that Qualcomm (NASDAQ:QCOM) isn’t in the portfolio. The company is one of the standout mobile chip providers.

Keep in mind that SMH shouldn’t represent a sizeble portion of an investor’s portfolio (say, no more than 5%). It’s simply too risky. But it could provide some extra juice for those who want to benefit from a rebound in semis, which could be in the early stages right now as mobile continues to grow.